The present invention relates to a timing apparatus, specifically a light clock. The light clock keeps time by incrementing a counter that functions as a timer by measuring an interval it takes a light pulse to travel a preset distance in either an open or a closed loop.
Current technology for time measurement relies on mechanical action, such as wound springs, pendulum, or the measured interval of a regular occurrence of a natural phenomena. One current example is a quartz clock. A quartz crystal vibrates at an ultrasonic frequency when exposed to an electric field, a phenomenon known as the piezoelectric effect. These vibrations of the crystal are constant and deliver a virtually frictionless beat to the counting mechanism of the clock, thus allowing a cycle upon which to base a timepiece.
Another such example is the frequency of radiation produced when an atom makes a quantum jump between two accurately defined energy levels. One current example is a cesium atomic clock. In 1967, the 13th General Conference of Weights and Measures redefined the second as xe2x80x9c9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.xe2x80x9d Also, unlike quartz crystals, cesium atoms don""t wear out. They can oscillate forever without any distortion whatsoever, but the lasers and electronics needed to run an atomic clock are very expensive and complex.
However all such methods of measuring time are subject to relativity and atomic clocks need constant recalibration to compensate for these relativistic effects. Since the speed of light is a constant, it can be utilized to create a nonrelative means of measuring time. By utilizing a light pulse and a known preset distance in the relative state of an observer, a time interval can be determined by dividing the speed of light by the known predetermined distance.
The present invention is a light clock, which has a light transmission device with either an open loop or a closed loop of a known predetermined distance for light pulse transmission. By dividing the speed of light by the known predetermined distance of the light transmission device, a time interval can be established and a counter incremented every time the light pulse is detected to create the light clock.
In a first embodiment, the light clock with a light pulse transmission device having a light pulse entry point and a light pulse exit point. This is an open loop a light pulse transmission device. A light pulse source generates a light pulse onto the light pulse entry point for transmission through the light pulse transmission device. The light pulse, upon exit at the light pulse exit point impinges upon a light pulse detector which detects the light pulse and provides an output signal upon light pulse detection. A counter is then incrementally increased upon receipt of the output signal of the light pulse detector. The counter is incremented either with a predetermined time interval, because the path length is known, in which case the light detector needs only to detect the light upon completion of the light pulse travel or it is incremented by the detected time it takes to travel a light pulse path, in which case the light pulse needs to be detected both at initiation and completion of any segment or the complete light pulse path. The light pulse may be detected at any point on the path. In one embodiment, the light pulse transmission device is circular meaning a housing which is cylindrical. In another embodiment the light pulse transmission device has a housing which is in a rectangular shape. In these embodiments one may use fully or partially reflecting mirrors or mirrored surfaces. In another embodiment, the light pulse transmission device is a fiber optic cable. Optionally, in any of these embodiments, the light pulse source may be initiated by the counter, the light pulse detector, or a controller.
In yet another embodiment, a light clock has a light pulse transmission device having a light pulse source entry point. This is a closed loop light pulse transmission device. There is a light pulse source initially generating a light pulse onto the light pulse source entry point, a light pulse detector for detecting the light pulse within the closed loop and providing an output signal upon light pulse detection, a light pulse amplifier within the closed loop for amplifying the light pulse, a counter which is then incrementally increased upon receipt of the output signal of the light pulse detector. The closed loop light pulse transmission device may be either a closed loop having mirrored surfaces with at least three points of reflection having a light pulse source entry point, preferably with one of the three mirrored surfaces being only partially reflecting, or a closed loop fiber optic cable of a known length. Preferably the light pulse transmission device is a closed loop fiber optic cable of a known length having a light pulse source entry point. Optionally, in any of these embodiments, the light pulse amplifier may be initiated by the counter, the light pulse detector, or a controller. Also in any of these embodiments, modulation of the light pulse amplifier may be initiated by the controller.